: Implicit learning refers to the non-intentional acquisition of knowledge about structural relations between objects or events, without awareness of what has been learned. It underlies our ability to adapt to new environments and makes our world predictable. Implicit learning is distinct from the explicit, conscious, forms of learning, and it depends upon different neural substrates. The long-term objective of this research proposal is to investigate age-related differences in implicit learning of sequential regularities in the environment, and in the ability to gain explicit knowledge of such regularities. The specific aims are to identify age-related differences in: (1) implicit learning of non-spatial sequential patterns; (2) ability to gain explicit knowledge of such patterns, and (3) the effects of trying to discover a pattern on implicit learning of sequential patterns. To achieve these goals, two experiments are proposed in which young and old adults complete six or seven sessions of an Alternating Serial Reaction Time (ASRT) task in which they respond to non-spatially arranged sequential patterns of letters containing subtle regularities. These experiments will provide insights into the selective losses that accompany normal aging, and could be helpful in designing educational and rehabilitation techniques for relearning skills after strokes or accidents.